A systematic review and meta-analysis of the diagnostic accuracy of biparametric prostate MRI for prostate cancer in men at risk

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI), the use of three multiple imaging sequences, typically T2-weighted, diffusion weighted (DWI) and dynamic contrast enhanced (DCE) images, has a high sensitivity and specificity for detecting significant cancer. Current guidance now recommends its use prior to biopsy. However, the impact of DCE is currently under debate regarding test accuracy. Biparametric MRI (bpMRI), using only T2 and DWI has been proposed as a viable alternative. We conducted a contemporary systematic review and meta-analysis to further examine the diagnostic performance of bpMRI in the diagnosis of any and clinically significant prostate cancer.

METHODS

A systematic review of the literature from 01/01/2017 to 06/07/2019 was performed by two independent reviewers using predefined search criteria. The index test was biparametric MRI and the reference standard whole-mount prostatectomy or prostate biopsy. Quality of included studies was assessed by the QUADAS-2 tool. Statistical analysis included pooled diagnostic performance (sensitivity; specificity; AUC), meta-regression of possible covariates and head-to-head comparisons of bpMRI and mpMRI where both were performed in the same study.

RESULTS

Forty-four articles were included in the analysis. The pooled sensitivity for any cancer detection was 0.84 (95% CI, 0.80-0.88), specificity 0.75 (95% CI, 0.68-0.81) for bpMRI. The summary ROC curve yielded a high AUC value (AUC = 0.86). The pooled sensitivity for clinically significant prostate cancer was 0.87 (95% CI, 0.78-0.93), specificity 0.72 (95% CI, 0.56-0.84) and the AUC value was 0.87. Meta-regression analysis revealed no difference in the pooled diagnostic estimates between bpMRI and mpMRI.

CONCLUSIONS

This meta-analysis on contemporary studies shows that bpMRI offers comparable test accuracies to mpMRI in detecting prostate cancer. These data are broadly supportive of the bpMRI approach but heterogeneity does not allow definitive recommendations to be made. There is a need for prospective multicentre studies of bpMRI in biopsy naïve men.

Sacral Insufficiency Fracture Following Pelvic Radiotherapy in Gynaecological Malignancies: Development of a Predictive Model

AIMS

To investigate the time-to-event and the evolution of sacral insufficiency fractures in gynaecological patients receiving pelvic external beam radiotherapy (EBRT) in relation to dosimetric and imaging parameters across a spectrum of radiotherapy delivery techniques, and to develop a predictive model with a clinical nomogram to identify those at risk of sacral insufficiency fracture.

MATERIALS AND METHODS

Patients who received radical or adjuvant pelvic EBRT for gynaecological malignancy between 2014 and 2019 were identified. The data collected were: demographics and clinical details; radiotherapy planning data: dose, fractionation, technique (fixed-field intensity-modulated radiotherapy, adaptive arc, and non-adaptive arc), 60 Gy simultaneous integrated boost. Each plan was examined to determine the sacral dose in 5%/Gy₃ increments. Follow-up magnetic resonance scans were reviewed for insufficiency fractures, defined as linear low T1-weighted signal intensity with a high short-T1 inversion recovery (STIR) signal. The site of insufficiency fracture was recreated on the planning computed tomography, the dose to insufficiency fracture contours was recorded and insufficiency fractures were determined as healed with resolution of high STIR signal. Univariable analysis was conducted of the clinical variables. The area under the receiver operator characteristic curve and odds ratio of the risk prediction model with 95% confidence interval are reported with a nomogram for use in clinical practice.

RESULTS

115 patients were identified; the median imaging follow-up was 12 months (2-47). 37.4% developed sacral insufficiency fractures; 93.0% were detected within 12 months of EBRT. At the final radiological follow-up, 83.7% of insufficiency fractures remained active. The radiotherapy delivery technique was not associated with insufficiency fracture after adjusting for patient age (P = 0.115). The location of the 60 Gy simultaneous integrated boost planning target volume did not impact upon the site of insufficiency fracture or the dose received by the insufficiency fracture sites. Age and V40Gy₃ are predictors for insufficiency fracture and form the clinical risk model (receiver operator characteristic 0.72).

CONCLUSIONS

Age and V40Gy₃ predict sacral insufficiency fractures; future work should focus on optimising radiotherapy planning with adoption of a bone-sparing planning approach for those patients at high risk of insufficiency fracture.

Diagnostic yields in patients with suspected prostate cancer undergoing MRI as the first-line investigation in routine practice

AIM

To document cancer yields of magnetic resonance imaging (MRI)-directed biopsies in men with suspected prostate cancer referred to secondary care.

MATERIALS AND METHODS

Men with suspected cancer undergoing multiparametric prostate MRI as the first-line investigation were included in the present study. Systematic transrectal prostate biopsies with/without cognitive targeted biopsies were performed. Diagnostic yields of International Society of Urological Pathology (ISUP) ≥2 cancers by the Prostate Imaging Reporting and Data System (PI-RADS) category were recorded. Impacts of prostate-specific antigen (PSA) density on biopsy results and yields of non-targeted biopsies in MRI non-suspicious prostate sextants assessed.

RESULTS

Of 262 men (90.5% biopsy naive), 86 (33%) MRI examinations were negative (PI-RADS 1-2) and 176 (67%) positive (PI-RADS 3: 8%; PI-RADS 4: 21%; PI-RADS 5: 38%). Two hundred and thirteen of 262 patients underwent a biopsy. ISUP ≥2 cancer detection rates were 8% (5/61) for PI-RADS 1-2, 18% (3/17) for PI-RADS 3, 49% (22/45) for PI-RADS 4, and 80% (72/90) for PI-RADS 5. Proportions of ISUP ≥2 increased with higher PSA densities in positive patients (%ISUP ≥2 for PSA density groups <0.12, 0.12 to <0.15 and ≥ 0.15 was 0%, 0%, 25% for PI-RADS 3, 21%, 33%, 68% for PI-RADS 4 and 40%, 83%, 89% for PI-RADS 5 respectively). ISUP ≥2 cancers were twice as likely in tumour adjacent sextants (52% versus 24%), without upgrading of gland level histology from insignificant to clinically significant prostate cancer by the sampling of normal-appearing tumour non-adjacent sextants.

CONCLUSIONS

One third of men can avoid biopsy after negative MRI. Cancer detection rates increase with PSA density values within positive MRI suspicion categories. Sampling normal-appearing tumour non-adjacent sextants may be unnecessary for whole-gland therapy.

Abstract P5-01-01: Adding whole-body MRI to body CT scans when evaluating response to systemic anti-cancer therapies alters treatment decisions in metastatic breast cancer

Introduction

Accurate evaluation of disease extent and response to systemic anti-cancer therapy (SACT) is key to the clinical management of patients with metastatic breast cancer. By identifying disease distribution and response (particularly progression prior to symptomatic deterioration), imaging aids therapy choices and may maximise quality of life. Whole body MRI (WB-MRI) has increased accuracy for detecting liver and bone disease in breast cancer; however, its potential impact on patient management is largely unexplored. Thus, the purpose of this study was to evaluate the added value of WB-MRI with standard of care CT scans for clinical decision making in routine practice for patients with metastatic breast cancer.

Methods

All patients with metastatic breast cancer who had undergone WB-MRI between 1st April 2009 and 31st March 2016 were screened for this study. Those who had undergone a CT scan of the chest, abdomen and pelvis (CT-CAP) within 14 days of a WB-MRI date were eligible. Original radiology reports for the WB-MRI and CT-CAP were reviewed to establish the extent of reported disease and the SACT response assessment. Contemporaneous medical notes were reviewed to establish the impact of the paired imaging findings (and clinical review) with regard to therapy decisions per time point.

Results

210 pairs of WB-MRI and CT-CAP scans in 101 patients were eligible for analysis. The median age of the studied patients was 56 years (range 23 to 84 years). 46 examination pairs were baseline studies; 164 were undertaken for response assessments (1st line SACT = 46; 2nd line = 27; ≥3rd line = 58; no information = 33).

In 140 cases (66.7%) there were differences between the extent of disease reported by the WB-MRI and CT-CAP. Of these, 112 (80.0%) were due to the WB-MRI reporting additional sites of disease not evident on CT-CAP, mostly skeletal lesions. CT-CAP showed more disease in 10.0%, mostly lung lesions. 10.0% had some lesions evident only on WB-MRI and other lesions evident only on CT-CAP.

Of the 164 scan pairs performed for SACT response assessment, there were differences in the reported response to therapy in 46 cases (28.0%). 89.1% of disagreements were due to WB-MRI showing evidence of either disease progression (67.4%) or partial response (21.7%) that was reported as stable disease on CT-CAP.

Decisions to change SACT in response to disease progression reported by either/both imaging methods were made in 80 cases. Of these, treatment changes were made due to progression reported only on WB-MRI in 23 (28.8%) cases.

Discussion

This is a retrospective analysis of the real world use of WB-MRI and CT-CAP in the clinical practice of metastatic breast cancer, evaluating their impact on clinical care on a per time point basis. WB-MRI identified additional sites of disease (mostly bone) in over half of patients, which affected SACT decisions in a significant proportion of cases. In many cases, SACT changes would not have been made at the same time point without WB-MRI information. Further research is required to test the hypothesis that earlier identification of disease progression by WB-MRI leads to improved quality of life and patient outcomes.

Citation Format: Kosmin M, Makris A, Joshi PV, Ah-See M-L, Padhani AR. Adding whole-body MRI to body CT scans when evaluating response to systemic anti-cancer therapies alters treatment decisions in metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-01-01.

Abstract P4-21-36: Splenic enlargement and bone marrow hyperplasia in patients receiving trastuzumab-emtansine for metastatic breast cancer

Introduction

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate used for treatment of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. An association between T-DM1 and splenic enlargement was noted anecdotally on sequential whole-body MRI (WB-MRI) examinations. A retrospective analysis of WB-MRI examinations of patients on T-DM1 was undertaken to investigate the hypothesis that an increase in splenic volume is due to either a generalised hyperplasia of the bone marrow and reticulo-endothelial system and/or an increase in portal venous pressure.

Methods

12 patients underwent 29 serial WB-MRIs before and during T-DM1 therapy. Splenic volume, portal vein diameter, bone marrow muscle-normalised signal intensity (nSI), water diffusivity (apparent diffusion coefficient, ADC) and fat fraction were measured. Changes in splenic volume were analysed, and correlations between the measured variables were obtained.

Results

An increase in splenic volume was observed in 92% of patients. Mean splenic volume increased from 144cm3 (95%CI 110-177cm3) to 209cm3 (95%CI 161-257cm3) on T-DM1 therapy (p=0.006). Increase in splenic volume correlated with treatment duration (r2=0.71). Increase in normal bone marrow signal was seen (nSI 3.5 to 4.8, p=0.12), along with a decrease in fat fraction (64.3% to 57.3%, p=0.12), and reduced ADC (655µm2/s to 543µm2/s, p=0.11). No consistent changes to portal vein diameter were seen.

Discussion

An increase in splenic volume was consistently observed in patients on T-DM1 therapy. This was unrelated to portal vein changes but correlated with bone marrow hyperplasia. Caution should be applied when assessing metastatic disease in bone to avoid incorrectly attributing T-DM1-related changes in normal bone marrow to disease progression.

Citation Format: Kosmin M, Makris A, Jawad N, Miles D, Padhani AR. Splenic enlargement and bone marrow hyperplasia in patients receiving trastuzumab-emtansine for metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-36.

Management of patients with advanced prostate cancer: recommendations of the St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) 2015

The first St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) Expert Panel identified and reviewed the available evidence for the ten most important areas of controversy in advanced prostate cancer (APC) management. The successful registration of several drugs for castration-resistant prostate cancer and the recent studies of chemo-hormonal therapy in men with castration-naïve prostate cancer have led to considerable uncertainty as to the best treatment choices, sequence of treatment options and appropriate patient selection. Management recommendations based on expert opinion, and not based on a critical review of the available evidence, are presented. The various recommendations carried differing degrees of support, as reflected in the wording of the article text and in the detailed voting results recorded in supplementary Material, available at Annals of Oncology online. Detailed decisions on treatment as always will involve consideration of disease extent and location, prior treatments, host factors, patient preferences as well as logistical and economic constraints. Inclusion of men with APC in clinical trials should be encouraged.

Assessing response to treatment of bone metastases from breast cancer: what should be the standard of care?

Bone is the most common site for breast cancer metastases, occurring in up to 70% of those with metastatic disease. In order to effectively manage these patients, it is essential to have consistent, reproducible and validated methods of assessing response to therapy. We present current clinical practice of imaging response assessment of bone metastases. We also review the biology of bone metastases and measures of response assessment including clinical assessment, tumour markers and imaging techniques; bone scans (BSs), computed tomography (CT), positron emission tomography, magnetic resonance imaging (MRI) and whole-body diffusion-weighted MRI (WB DW-MRI). The current standard of care of BSs and CT has significant limitations and are not routinely recommended for the purpose of response assessment in the bones. WB DW-MRI has the potential to address this unmet need and should be evaluated in clinical trials.

The diagnostic accuracy and cost-effectiveness of magnetic resonance spectroscopy and enhanced magnetic resonance imaging techniques in aiding the localisation of prostate abnormalities for biopsy: a systematic review and economic evaluation

BACKGROUND

In the UK, prostate cancer (PC) is the most common cancer in men. A diagnosis can be confirmed only following a prostate biopsy. Many men find themselves with an elevated prostate-specific antigen (PSA) level and a negative biopsy. The best way to manage these men remains uncertain.

OBJECTIVES

To assess the diagnostic accuracy of magnetic resonance spectroscopy (MRS) and enhanced magnetic resonance imaging (MRI) techniques [dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DW-MRI)] and the clinical effectiveness and cost-effectiveness of strategies involving their use in aiding the localisation of prostate abnormalities for biopsy in patients with prior negative biopsy who remain clinically suspicious for harbouring malignancy.

DATA SOURCES

Databases searched--MEDLINE (1946 to March 2012), MEDLINE In-Process & Other Non-Indexed Citations (March 2012), EMBASE (1980 to March 2012), Bioscience Information Service (BIOSIS; 1995 to March 2012), Science Citation Index (SCI; 1995 to March 2012), The Cochrane Library (Issue 3 2012), Database of Abstracts of Reviews of Effects (DARE; March 2012), Medion (March 2012) and Health Technology Assessment database (March 2012).

REVIEW METHODS

Types of studies: direct studies/randomised controlled trials reporting diagnostic outcomes.

INDEX TESTS

MRS, DCE-MRI and DW-MRI. Comparators: T2-weighted magnetic resonance imaging (T2-MRI), transrectal ultrasound-guided biopsy (TRUS/Bx). Reference standard: histopathological assessment of biopsied tissue. A Markov model was developed to assess the cost-effectiveness of alternative MRS/MRI sequences to direct TRUS-guided biopsies compared with systematic extended-cores TRUS-guided biopsies. A health service provider perspective was adopted and the recommended 3.5% discount rate was applied to costs and outcomes.

RESULTS

A total of 51 studies were included. In pooled estimates, sensitivity [95% confidence interval (CI)] was highest for MRS (92%; 95% CI 86% to 95%). Specificity was highest for TRUS (imaging test) (81%; 95% CI 77% to 85%). Lifetime costs ranged from £3895 using systematic TRUS-guided biopsies to £4056 using findings on T2-MRI or DCE-MRI to direct biopsies (60-year-old cohort, cancer prevalence 24%). The base-case incremental cost-effectiveness ratio for T2-MRI was <£30,000 per QALY (all cohorts). Probabilistic sensitivity analysis showed high uncertainty surrounding the incremental cost-effectiveness of T2-MRI in moderate prevalence cohorts. The cost-effectiveness of MRS compared with T2-MRI and TRUS was sensitive to several key parameters.

LIMITATIONS

Non-English-language studies were excluded. Few studies reported DCE-MRI/DW-MRI. The modelling was hampered by limited data on the relative diagnostic accuracy of alternative strategies, the natural history of cancer detected at repeat biopsy, and the impact of diagnosis and treatment on disease progression and health-related quality of life.

CONCLUSIONS

MRS had higher sensitivity and specificity than T2-MRI. Relative cost-effectiveness of alternative strategies was sensitive to key parameters/assumptions. Under certain circumstances T2-MRI may be cost-effective compared with systematic TRUS. If MRS and DW-MRI can be shown to have high sensitivity for detecting moderate/high-risk cancer, while negating patients with no cancer/low-risk disease to undergo biopsy, their use could represent a cost-effective approach to diagnosis. However, owing to the relative paucity of reliable data, further studies are required. In particular, prospective studies are required in men with suspected PC and elevated PSA levels but previously negative biopsy comparing the utility of the individual and combined components of a multiparametric magnetic resonance (MR) approach (MRS, DCE-MRI and DW-MRI) with both a MR-guided/-directed biopsy session and an extended 14-core TRUS-guided biopsy scheme against a reference standard of histopathological assessment of biopsied tissue obtained via saturation biopsy, template biopsy or prostatectomy specimens.

STUDY REGISTRATION

PROSPERO number CRD42011001376.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Prostate MRI: who, when, and how? Report from a UK consensus meeting

The current pathway for men suspected of having prostate cancer [transrectal biopsy, followed in some cases by magnetic resonance imaging (MRI) for staging] results in over-diagnosis of insignificant tumours, and systematically misses disease in the anterior prostate. Multiparametric MRI has the potential to change this pathway, and if performed before biopsy, might enable the exclusion of significant disease in some men without biopsy, targeted biopsy in others, and improvements in the performance of active surveillance. For the potential benefits to be realized, the setting of standards is vital. This article summarizes the outcome of a meeting of UK radiologists, at which a consensus was achieved on (1) the indications for MRI, (2) the conduct of the scan, (3) a method and template for reporting, and (4) minimum standards for radiologists.

Abstract P1-06-01: Upregulation of metabolism as a potential resistance mechanism to bevacizumab in primary breast cancer

Background: Recently the FDA has withdrawn the indication for bevacizumab in metastatic breast cancer after several clinical studies failed to demonstrate an overall survival benefit. These studies however did report an increase in response rates to chemotherapy and improvement in progression free survival, suggesting a pattern of response to the drug followed by the development of resistance. We have little knowledge of the molecular mechanisms driving the development of resistance to bevacizumab. To better understand these mechanisms, we have conducted a window of opportunity study using a single cycle of bevacizumab with detailed pharmacodynamic assessments using gene expression arrays and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

Methods: After ethical approval, 47 newly diagnosed locally advanced breast cancer patients were prospectively enrolled in this trial. Patients received single dose bevacizumab (15mg/ kg) 2 weeks prior to neoadjuvant chemotherapy and underwent core biopsies for gene expression and immunohistochemistry analysis and DCE-MRI scans before and 2 weeks after bevacizumab. 35 patients who had invasive ductal carcinoma together with good quality MRI scans and core biopsies before and after bevacizumab were included in this analysis. Pharmacokinetic (PK) modelling techniques were used to quantify PK parameters (Ktrans, kep, ve) from the DCE-MRI data. Gene expression profiling was performed using the Affymetrix Human Exon 1.0 ST arrays.

Results: The majority of patients (28/35) showed a significant reduction in vessel permeability and blood flow of at least 30% following bevacizumab, with a mean decrease in the forward transfer constant (P &lt; 0.0001) and the reverse rate constant kep (P &lt; 0.0001). From gene expression and immunohistochemistry analyses, we identified several key metabolism-related genes that are significantly up-regulated after bevacizumab treatment, including pyruvate dehydrogenase kinase isozyme 1 (PDK1) (fig.1) and carbonic anhydrase 9 (CA9). In addition, we found a number of interesting genes that are down-regulated after bevacizumab treatment, including sulfatase-1 (SULF1), and cyclin E1 (CCNE1).

Discussion: This study highlights that the combination of DCE-MRI and gene expression arrays can lead to an improved understanding of the molecular mechanisms governing response and resistance to anti-angiogenic therapy. Heterogeneity of response to bevacizumab was demonstrated, with some tumours showing increases or no change in Ktrans and others marked reductions, which may be of value in early stratification for therapy maintenance. Furthermore, the gene expression analysis showed activation of pathways, which could contribute to the development of resistance. For example, we observed significant up regulation of genes involved in regulating the switch from mitochondrial metabolism to glycolysis, such as PDK1. This suggests that using bevacizumab with the other targeted agents such as Dichloroacetate, a PDK1 inhibitor might be helpful in overcoming the development of resistance and ultimately lead to improved patient survival. Our preclinical studies strongly support this possibility.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-06-01.

Phase Ib trial of radiotherapy in combination with combretastatin-A4-phosphate in patients with non-small-cell lung cancer, prostate adenocarcinoma, and squamous cell carcinoma of the head and neck

BACKGROUND

The vascular disrupting agent combretastatin-A4-phosphate (CA4P) demonstrated antitumour activity in preclinical studies when combined with radiation.

METHODS

Patients with non-small-cell lung cancer (NSCLC), prostate adenocarcinoma, and squamous cell carcinoma of the head and neck (SCCHN) received 27 Gy in 6 fractions treating twice weekly over 3 weeks, 55 Gy in 20 fractions over 4 weeks, and 66 Gy in 33 fractions over 6 weeks respectively. CA4P was escalated from 50 mg/m2 to 63 mg/m2. CA4P exposure was further increased from one to three to six doses. Patients with SCCHN received cetuximab in addition.

RESULTS

Thirty-nine patients received 121 doses of CA4P. Dose-limiting toxic effects (DLTs) of reversible ataxia and oculomotor nerve palsy occurred in two patients with prostate cancer receiving weekly CA4P at 63 mg/m2. DLT of cardiac ischaemia occurred in two patients with SCCHN at a weekly dose of 50 mg/m2 in combination with cetuximab. Three patients developed grade 3 hypertension. Responses were seen in 7 of 18 patients with NSCLC. At 3 years, 3 of 18 patients with prostate cancer had prostate-specific antigen relapse.

CONCLUSIONS

Radiotherapy with CA4P appears well tolerated in most patients. The combination of CA4P, cetuximab, and radiotherapy needs further scrutiny before it can be recommended for clinical studies.

[Diagnose importance of multiparametric magnetic resonance tomography for prostate cancer]

Prostate cancer is biologically and clinically a heterogeneous disease which makes imaging evaluation challenging. Magnetic resonance imaging (MRI) has considerable potential to improve prostate cancer detection and characterization. Until recently morphologic MRI has not been routinely incorporated into clinical care because of its limitation to detect, localize and characterize prostate cancer. Performing prostate gland MRI using functional techniques has the potential to provide unique information regarding tumor behavior, including treatment response. In order for multiparametric MRI data to have an impact on patient management, the collected data need to be relayed to clinicians in a standardized way for image construction, analysis and interpretation. This will ensure that patients are treated effectively and in the most appropriate way. Scoring systems similar to those employed successfully for breast imaging need to be developed.

Bony metastases: assessing response to therapy with whole-body diffusion MRI

There are no universally accepted methods for assessing tumour response in skeletal sites with metastatic disease; response is assessed by a combination of imaging tests, serum and urine biochemical markers and symptoms assessments. Whole-body diffusion magnetic resonance imaging excels at bone marrow assessments at diagnosis and for therapy evaluations. It can potentially address unmet clinical and pharmaceutical needs for a reliable measure of tumour response. Signal intensity on high b-value images and apparent diffusion coefficient values can be related to underlying biophysical properties of skeletal metastases. Four patterns of change in response to therapy are described this review. Therapy response criteria need to be tested in prospective clinical studies that incorporate conventional measures of patient benefit.

Integrating multiparametric prostate MRI into clinical practice

Multifunctional magnetic resonance imaging (MRI) techniques are increasingly being used to address bottlenecks in prostate cancer patient management. These techniques yield qualitative, semi-quantitative and fully quantitative biomarkers that reflect on the underlying biological status of a tumour. If these techniques are to have a role in patient management, then standard methods of data acquisition, analysis and reporting have to be developed. Effective communication by the use of scoring systems, structured reporting and a graphical interface that matches prostate anatomy are key elements. Practical guidelines for integrating multiparametric MRI into clinical practice are presented.

Abstract P2-09-28: Integrated Gene Expression and MRI Analysis To Assess Early Therapeutic Response to Bevacizumab in Primary Breast Cancer

Background: Bevacizumab is an approved drug for advanced breast cancer alongside chemotherapy. To date there is no biomarker proven to be effective in patient stratification. To address this, a window of opportunity study was designed where bevacizumab is administered as a short-term first line treatment with a detailed pharmacodynamic assessment to identify the patients who are most likely to benefit from this therapy. This assessment consisted of Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) and gene expression analysis.

Method: This is an on going two-centre, Phase II, non-randomised study. 43 locally advanced breast cancer patients aged &gt;18 years, with performance status 0-1 who have adequate bone marrow, renal and liver functions have been enrolled. A single infusion of bevacizumab (15mg/kg) was given prior to commencement of neoadjuvant chemotherapy. DCE-MRI and core biopsies for exon gene array analysis were performed both at baseline and 2 weeks after bevacizumab. Pharmacokinetic modelling of DCE-MRI was used to quantify the volume transfer constant Ktrans, the rate constant kep, and the fractional volume of the extra-vascular extracellular space ve. The median pharmacokinetic parameter values over the tumour volumes of interest were then computed both pre-and post-bevacizumab.

Results: Our initial gene expression analysis from 21 patients showed a high variability in the response. This was true for both single gene analysis and pathway signatures. In particular the expression fold changes of hypoxia and proliferation signatures after bevacizumab ranged from a minimum of 0.6 fold decrease to a maximum of 4.3 fold increase. Interestingly, fold changes in both these signatures were significantly positively correlated (Spearman rho=0.81, P&lt;0.001). Changes in the proliferation signature were significantly inversely correlated with changes in mean and median ve (rho=-0.57, P&lt;0.01 in both cases). Changes in the hypoxia signature were significantly inversely correlated with changes in mean and median kep (rho=-0.48, p=0.03 and rho=-0.58, p=0.007 respectively). Significantly over-represented pathways amongst genes up-regulated after bevacizumab were T-cell activation, inflammation, PDGF and apoptosis signalling. Discussion: Our initial results provide several potentially important avenues for further research, which may be useful in the identification of new therapeutic approaches. For example, the unexpected correlation of induction of hypoxia and proliferation in the same tumours has important implications for combination therapy. Furthermore, patients whose tumours showed the largest reduction in kep, a measure of vascular leakiness, also showed the greatest increase in hypoxia. In addition, patients who experienced the largest reduction in ve showed the highest fold change in proliferation. Although these results are preliminary and will need to be confirmed at study completion, they illustrate how the integrated analysis of DCE-MRI pharmacokinetic parameters and the corresponding gene expression profiles may enable an improved understanding of the mechanisms governing response and resistance to bevacizumab.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-28.

The relationship of the neo-angiogenic marker, endoglin, with response to neoadjuvant chemotherapy in breast cancer

Endoglin (CD105) is upregulated in endothelial cells of tissues undergoing neovascularisation. A greater number of CD105-positive vessels predicts poor survival in breast cancer. We examine whether CD105 expression predicts response to neoadjuvant chemotherapy. Fifty-seven women (median age 50 years, range 29-70) received neoadjuvant chemotherapy for operable breast cancer. Immunohistochemical staining using monoclonal antibodies to CD105 and CD34 was performed on pretreatment biopsies and post-treatment surgical specimens. Individual microvessels were counted in 10 random fields at x 200 magnification. Median counts were correlated with clinical and pathological response using the Mann-Whitney U-test. Forty-five out of fifty-seven patients (79%) responded clinically, 22 (39%) responded pathologically. On pretreatment biopsies, clinical responders had significantly lower median CD105-positive vessel counts than nonresponders (median counts 5 and 9.3/high-power field (hpf), median difference=4.0/hpf, 95% CI 0.5-8.0/hpf, P=0.02). For pathological responders and nonresponders, median counts were 4.8 and 5.5/hpf (median difference -0.5/hpf, 95% CI=-2.5-2.0/hpf, P=0.77). CD34 expression (total microvessel density) did not correlate with response. Pretreatment CD105 expression predicts for clinical response to chemotherapy, with a lower initial count being favourable. Patients with high baseline new vessel counts or increased counts after conventional therapy may benefit from additional antiangiogenic therapy.

Cost-effectiveness of screening with contrast enhanced magnetic resonance imaging vs X-ray mammography of women at a high familial risk of breast cancer

Contrast enhanced magnetic resonance imaging (CE MRI) is the most sensitive tool for screening women who are at high familial risk of breast cancer. Our aim in this study was to assess the cost-effectiveness of X-ray mammography (XRM), CE MRI or both strategies combined. In total, 649 women were enrolled in the MARIBS study and screened with both CE MRI and mammography resulting in 1881 screens and 1–7 individual annual screening events. Women aged 35–49 years at high risk of breast cancer, either because they have a strong family history of breast cancer or are tested carriers of a BRCA1, BRCA2 or TP53 mutation or are at a 50% risk of having inherited such a mutation, were recruited from 22 centres and offered annual MRI and XRM for between 2 and 7 years. Information on the number and type of further investigations was collected and specifically calculated unit costs were used to calculate the incremental cost per cancer detected. The numbers of cancer detected was 13 for mammography, 27 for CE MRI and 33 for mammography and CE MRI combined. In the subgroup of BRCA1 (BRCA2) mutation carriers or of women having a first degree relative with a mutation in BRCA1 (BRCA2) corresponding numbers were 3 (6), 12 (7) and 12 (11), respectively. For all women, the incremental cost per cancer detected with CE MRI and mammography combined was £28 284 compared to mammography. When only BRCA1 or the BRCA2 groups were considered, this cost would be reduced to £11 731 (CE MRI vs mammography) and £15 302 (CE MRI and mammography vs mammography). Results were most sensitive to the unit cost estimate for a CE MRI screening test. Contrast-enhanced MRI might be a cost-effective screening modality for women at high risk, particularly for the BRCA1 and BRCA2 subgroups. Further work is needed to assess the impact of screening on mortality and health-related quality of life.

Imaging tumor angiogenesis: functional assessment using MDCT or MRI?

Functional imaging using multidetector row computed tomography and dynamic contrast-enhanced magnetic resonance imaging are increasingly advocated for assessment of tumor vascularity because these techniques provide excellent anatomic imaging and reliable quantitative perfusion data and are easily incorporated into routine examinations. However, differences in acquisition techniques, mathematical analysis, measurement parameters, and propensity to artifacts influence the choice of imaging modality, which is explored in this review.

Dynamic contrast-enhanced magnetic resonance imaging is a poor measure of rectal cancer angiogenesis

BACKGROUND

The aim of this study was to investigate the use of magnetic resonance imaging (MRI) for non-invasive measurement of rectal cancer angiogenesis and hypoxia.

METHODS

Fifteen patients with rectal adenocarcinoma underwent preoperative dynamic contrast-enhanced (DCE) and blood oxygenation level-dependent (BOLD) MRI. Microvessel density (CD31 level), and expression of vascular endothelial growth factor (VEGF) and carbonic anhydrase (CA) 9 were measured immunohistochemically in histological tumour sections from 12 patients. Serum VEGF levels were also measured in 14 patients. Correlations between quantitative imaging indices and immunohistochemical variables were examined.

RESULTS

There was good correlation between circulating VEGF and CD31 expression (r(S) = 0.88, P < 0.001). CD31 expression did not correlate with any dynamic MRI parameter, except transfer constant, with which it correlated inversely (r(S) = -0.65, P = 0.022). Tissue and circulating VEGF levels did not correlate, and neither correlated with any tumour DCE MRI parameter. No relationship was seen between BOLD MRI and CA-9 expression.

CONCLUSION

The negative correlation between transfer constant (reflecting tumour blood flow and microvessel permeability) with CD31 expression is paradoxical. DCE MRI methods for assessing tissue vascularity correlate poorly with histological markers of angiogenesis and hypoxia, suggesting that DCE MRI does not simply reflect static histological vascular properties in patients with rectal cancer.

A phase I study of BIBF 1120, an orally active triple angiokinase inhibitor (VEGFR, PDGFR, FGFR) given continuously to patients with advanced solid tumours, incorporating dynamic contrast enhanced magnetic resonance imaging (DCE-MRI)

3015

Background: BIBF 1120 is a potent inhibitor of VEGFR, PDGFR, FGFR kinases, and of members of the Src family of tyrosine kinases (Src, Lck, Lyn). Methods: Patients (Pts) with advanced solid tumours were enrolled. BIBF 1120 was administered orally once daily (q.d.) continuously, starting at 100 mg/day. Dosing was later amended to twice daily (b.i.d.) in view of transaminitis seen with q.d. dosing. DCE-MRI studies were performed at baseline, days 2 and 28. All pts underwent pharmacokinetic (PK) sampling. Results: 51 pts (26M/25F; median age 57 y, range 22–78 y; ECOG PS 0/1 = 22/27) were treated at: 100 mg q.d. (n = 6), 200 mg q.d. (n = 6), 300 mg q.d. (n = 7), 400 mg q.d. (n = 16), 450 mg q.d. (n = 5); 250 mg b.i.d. (n = 11). Median treatment duration was 57 days (range: 1 day– 22 m). The most common toxicities were nausea, vomiting, diarrhoea, abdominal pain and fatigue, all ≤ grade (G)2. Asymptomatic, reversible elevation of liver enzymes which was dose limiting in 2/5 pts at 450 mg q.d. defined the MTD at 400 mg q.d. At 250 mg b.i.d., 2/11 pts had DLT (G3 elevation in liver enzymes: n = 1; G3 abdominal pain: n = 1). 44 pts treated for ≥2 m were assessable for response: 13 pts had SD for ≥3 m (median 7m, range 3–22 m; renal, prostate, colorectal, chondrosarcoma, leiomyomatosis, fibromatosis). 3 pts with renal cancer had SD for 8, 14+ and 22 m respectively. PK evaluations generally showed increasing gMean Cmax and AUC values with increasing doses, with high inter-patient variability. Tmax was ∼2h post-dosing. gMean t1/2 values ranged from 6.8–26.4h. DCE-MRI of target lesions in 35 pts showed significant antivascular/antiangiogenic effects in some patients and dose cohorts, particularly at 200 mg q.d. and ≥400 mg q.d. DCE-MRI effects were most pronounced at 28 days, especially in metastatic liver lesions. Conclusions: BIBF 1120 is well-tolerated in patients with advanced solid malignancies and induces in vivo antiangiogenic effects detectable by DCE-MRI. Some patients experienced clinically meaningful disease stabilisation. The recommended dose for future Phase II studies was determined to be 250 mg b.i.d.

[Table: see text]

Effects of platinum/taxane based chemotherapy on acute perfusion in human pelvic tumours measured by dynamic MRI

Dynamic contrast enhanced MRI (DCE-MRI) is being used increasingly in clinical trials to demonstrate that vascular disruptive and antiangiogenic agents target tumour microcirculation. Significant reductions in DCE-MRI kinetic parameters are seen within 4–24 and 48 h of treatment with vascular disruptive and antiangiogenic agents, respectively. It is important to know whether cytotoxic agents also cause significant acute reductions in these parameters, for reliable interpretation of results. This study investigated changes in transfer constant (K^trans) and the initial area under the gadolinium curve (IAUGC) following the first dose of chemotherapy in patients with mostly gynaecological tumours. A reproducibility analysis on 20 patients (using two scans performed on consecutive days) was used to determine the significance of DCE-MRI parameter changes 24 h after chemotherapy in 18 patients. In 11 patients who received platinum alone or with a taxane, there were no significant changes in K^trans or IAUGC in either group or individual patient analyses. When the remaining seven patients (treated with a variety of agents including platinum and taxanes) were included (n=18), there were also no significant changes in K^trans. Therefore, if combination therapy does show changes in DCE-MRI parameters then the effects can be attributed to antivascular therapy rather than chemotherapy.

Antivascular cancer treatments: functional assessments by dynamic contrast-enhanced magnetic resonance imaging

New anticancer therapeutics that target tumor blood vessels promise improved efficacy and tolerability in humans. Early phase 1 drug trials have shown that the maximum tolerated dose may be inappropriate for more advanced clinical studies with efficacy endpoints. More advanced clinical trials have demonstrated that morphologic assessments of tumor response are of limited value for gauging the efficacy of treatment. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can serve as pharmacodynamic indicator of biological activity for antivascular cancer drugs by helping to define the biologically active dose. DCE-MRI studies may also predict the efficacy of treatment on the basis of changes observed. If DCE-MRI is to be used for the selection of antivascular drugs that advance into efficacy trials, then it will be necessary to develop standardized approaches to measurement and robust analytic approaches with clear accepted endpoints specified prospectively that have biological validity. Such developments will be essential for multicenter trials in which it will be necessary to establish effective cross-site standardization of measurements and evaluation.

The assessment of antiangiogenic and antivascular therapies in early-stage clinical trials using magnetic resonance imaging: issues and recommendations

Vascular and angiogenic processes provide an important target for novel cancer therapeutics. Dynamic contrast-enhanced magnetic resonance imaging is being used increasingly to noninvasively monitor the action of these therapeutics in early-stage clinical trials. This publication reports the outcome of a workshop that considered the methodology and design of magnetic resonance studies, recommending how this new tool might best be used.

Screening with magnetic resonance imaging and mammography of a UK population at high familial risk of breast cancer: a prospective multicentre cohort study (MARIBS)

BACKGROUND

Women genetically predisposed to breast cancer often develop the disease at a young age when dense breast tissue reduces the sensitivity of X-ray mammography. Our aim was, therefore, to compare contrast enhanced magnetic resonance imaging (CE MRI) with mammography for screening.

METHODS

We did a prospective multicentre cohort study in 649 women aged 35-49 years with a strong family history of breast cancer or a high probability of a BRCA1, BRCA2, or TP53 mutation. We recruited participants from 22 centres in the UK, and offered the women annual screening with CE MRI and mammography for 2-7 years.

FINDINGS

We diagnosed 35 cancers in the 649 women screened with both mammography and CE MRI (1881 screens): 19 by CE MRI only, six by mammography only, and eight by both, with two interval cases. Sensitivity was significantly higher for CE MRI (77%, 95% CI 60-90) than for mammography (40%, 24-58; p=0.01), and was 94% (81-99) when both methods were used. Specificity was 93% (92-95) for mammography, 81% (80-83) for CE MRI (p<0.0001), and 77% (75-79) with both methods. The difference between CE MRI and mammography sensitivities was particularly pronounced in BRCA1 carriers (13 cancers; 92%vs 23%, p=0.004).

INTERPRETATION

Our findings indicate that CE MRI is more sensitive than mammography for cancer detection. Specificity for both procedures was acceptable. Despite a high proportion of grade 3 cancers, tumours were small and few women were node positive. Annual screening, combining CE MRI and mammography, would detect most tumours in this risk group.

Tumour staging using magnetic resonance imaging in clinically localised prostate cancer: relationship to biochemical outcome after neo-adjuvant androgen deprivation and radical radiotherapy

AIMS

To evaluate the prognostic significance of magnetic resonance imaging (MRI) tumour stage in clinically localised prostate cancer.

MATERIALS AND METHODS

Between 1988 and 1999, 199 men with clinically localised prostate cancer (T -T4, N0/Nx, M0) were treated with neo-adjuvant androgen deprivation and radical radiotherapy, and were staged using MRI. Concordance between clinical tumour (cT) stage, as determined by digital rectal examination, and MRI tumour (mT) stage was assessed. Univariate and multivariate analyses using the Cox proportional hazards model were used to study the prognostic role of cT stage and mT stage in addition to established prognostic factors.

RESULTS

Of these 199 patients, 103 (52%) were upstaged on MRI, seven (3%) were downstaged, and in 89 (45%) cT and mT stages were concordant. With median follow-up of 3.8 years, 5-year freedom from prostate-specific antigen (PSA) failure was 48% (95% confidence interval (CI) 39-56%). On univariate analysis, freedom from PSA failure was associated with mT stage (P = 0.009) as well as Gleason score (P < 0.001) and initial PSA (P < 0.001), but not cT stage (P = 0.449). On multivariate analysis, Gleason score (P = 0.001), initial PSA (P < 0.001), but not mT stage (P = 0.112) remained independent determinants of freedom from PSA failure. For the subgroup of 149 patients with cT1-2 disease, mT stage was a significant predictor of increased risk of PSA failure on univariate analysis (P = 0.005), but not multivariate analysis (P = 0.19).

CONCLUSION

Freedom from PSA failure was more closely associated with mT stage than cT stage. Future studies are warranted to determine whether mT stage is an independent determinant of treatment outcome.

MRI for assessing antivascular cancer treatments

Selective antiangiogenesis and vascular targeting drugs hold out the promise of improved efficacy and tolerability for anticancer treatments. Early phase 1 drug trials have shown good tolerability for antiangiogenesis agents with biological activity below the maximum tolerated dose. Advanced clinical trials have demonstrated that morphological assessments of tumour response are of limited value in gauging the efficacy of treatment. MRI is a versatile technique which is sensitive to contrast mechanisms that can be affected by antivascular treatments; this use for MRI has been validated in xenografts and humans. Dynamic contrast-enhanced MRI (DCE-MRI), which demonstrates tissue perfusion and permeability, is being used clinically as a pharmacodynamic indicator of biological activity for antivascular cancer drugs. Early data show that DCE-MRI studies can define the biologically active dose and predict the efficacy of treatment on the basis of changes observed. MRI with macromolecular contrast media (MMCM) depicts microvessel permeability and fractional plasma volume. Xenograft studies with MMCM have shown great promise for evaluating antivascular treatments but this has not been used clinically. Intrinsic susceptibility-weighted MRI, which is sensitive to blood oxygenation and flow, is emerging as a technique that may be able to monitor vascular targeting therapies.

The pathway study: results of a pilot feasibility study in patients suspected of having lung carcinoma investigated in a conventional chest clinic setting compared to a centralised two-stop pathway

The best chance of cure in non-small cell lung cancer (NSCLC) is surgical resection, but UK rates of 8% compare poorly to 25% in the USA and Europe. Delays in diagnosis in the current UK system may be one reason for such discrepancy. To address this problem we set up a rapid diagnostic system and compared it to the conventional method of investigations in a pilot randomised trial.

METHODS

Eighty-eight patients were prospectively enrolled from three District General Hospitals and randomised to either investigation locally or to the rapid system at The Royal Marsden Hospital. The pilot end-points were feasibility and audit of radical treatment rates to enable estimates for patient numbers for the full study.

RESULTS

Forty-five and 43 patients were in the central and conventional arms, respectively (65% male, median age 69 years). There was a 4-week improvement in time to first treatment in those in the central arm (P=0.0025) with 13/30 (43%) and 9/27 (33%) patients having radical treatment in the central and conventional arms, respectively. Patients in the conventional arm felt the diagnostic process was too slow (P=0.02) while those in the central arm seemed to have a better care experience (P=0.01). There were significantly less visits to the general practitioner (GP) in the central arm (P=0.02).

CONCLUSIONS

This pilot study demonstrates that the full study is feasible but would require the commitment and involvement of a large number of patients and physicians. The results show several advantages to investigations and diagnosis in the central arm, particularly in time to treatment initiation, patient satisfaction and rate of radical treatments. The improved rate of radical treatment could lead to an improved survival rate.

Functional MRI for anticancer therapy assessment

Anticancer drug discovery and development are experiencing a paradigm shift from cytotoxic therapies to more selective therapies that target underlying oncogenic abnormalities. Many newer therapies are cytostatic, for which objective tumour shrinkage is an inappropriate response parameter. There is a growing need to develop surrogate endpoints of drug efficacy to speed up the process of finding effective drug combinations for phase III trials. This review focuses on the developing field of functional magnetic resonance imaging (MRI) and its potential applications in the pharmacodynamic evaluation of existing and new cancer therapeutics. Dynamic contrast enhanced MRI, which is currently being used to evaluate anti-angiogenic, and anti-vascular agents in human trials will be reviewed in detail. The requirements that must be met before incorporating functional MRI techniques into clinical protocols are also discussed.

A multicentre phase II trial of primary chemotherapy with cisplatin and protracted venous infusion 5-fluorouracil followed by chemoradiation in patients with carcinoma of the oesophagus

BACKGROUND

We undertook a multicentre phase II trial to evaluate the safety and efficacy of primary chemotherapy followed by chemoradiation for localised adenocarcinoma or squamous carcinoma of the oesophagus.

PATIENTS AND METHODS

Chemotherapy comprised five 3-weekly cycles of cisplatin and protracted continuous infusion 5-fluorouracil, with conformally planned radiotherapy commencing at the start of the fifth cycle.

RESULTS

The planned treatment programme was completed by 39 of 72 patients (54%), and a further 13% completed chemotherapy and proceeded to surgical oesophagectomy. Response rates to chemotherapy and to the entire treatment programme were 47% [95% confidence interval (CI) 34% to 60%] and 56% (CI 43% to 68%). The dysphagia score improved in 54% of patients. The median survival duration was 14.6 months with 1- and 2-year survival rates of 58.7% and 44.1%, respectively. Grade III/IV chemotherapy-related toxicity occurred in 38% of patients, and there were no treatment-related deaths.

CONCLUSIONS

This is a feasible and active treatment regimen providing palliative benefits for patients with poor-prognosis localised oesophageal cancer.

Applications of sliding window reconstruction with cartesian sampling for dynamic contrast enhanced MRI

Applications of dynamic contrast enhanced MR imaging are increasing and require both high spatial resolution and high temporal resolution. Perfusion studies using susceptibility contrast in particular require very high temporal resolution. The sliding window reconstruction is a technique for increasing temporal resolution. It has previously been applied to radial and spiral sampling, but these schemes require extensive correction and interpolation during image reconstruction. Fourier raw data can be reconstructed simply and quickly using the fast fourier transform (FFT). This paper presents a new Fourier-based sampling scheme and sliding window reconstruction that facilitates fast scanning without needing correction or interpolation. This technique can be used on virtually any MR scanner since it requires no specialized hardware. It is implemented here as a dual gradient echo sequence providing simultaneous T(1)- and T(2)*-weighted images with a time resolution of 1.1 s.

Clinical and immunological assessment of Mycobacterium vaccae (SRL172) with chemotherapy in patients with malignant mesothelioma

The objectives of this study were to determine the toxicity of intratumoural/intrapleural SRL172 in addition to intradermal SRL172 and standard chemotherapy (mitomycin-C, vinblastine and cisplatin) in patients with malignant mesothelioma. Patients received chemotherapy (mitomycin-C: 8 mg m(-2), vinblastine: 6 mg m(-2), cisplatin 50 mg m(-2)) on a 3-weekly basis for up to six courses. IP SRL172 injections were given 3-weekly prior to chemotherapy and escalated in groups of three patients from 1 microg to 1 mg bacilli in 10-fold increments. Patients were also given ID SRL172 at a dose of 1 mg bacilli 4-weekly. Patients were assessed for toxicity after each course of chemotherapy and for response by CT imaging. Immuno-haematological parameters were analyzed pre-treatment and 1 month after completion of treatment. There was no dose limiting toxicity with IP SRL172 although there was greater toxicity at the highest dose (n=13). There were six out of 16 partial responses (37.5%). Haemato-immunological parameters, measured in seven patients pre and post-therapy, revealed that response rate correlated with a decrease in platelet count and there was an increase in activation of natural killer cells and a decrease in the percentage of IL-4 producing T cells in all tested patients post-treatment. SRL172 can be given safely into tumour deposits and the pleural cavity in patients with malignant mesothelioma and we have established the dose for phase II testing.

Non-invasive methods of assessing angiogenesis and their value in predicting response to treatment in colorectal cancer

BACKGROUND

Tumour neoangiogenesis can be assessed non-invasively by measuring angiogenic cytokine concentrations in peripheral circulation and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The aim of this study was to assess whether these methods can predict and monitor response to treatment in patients with rectal cancer treated with preoperative chemoradiotherapy.

METHODS

Serum and plasma vascular endothelial growth factor levels were measured in 31 patients with T3/T4 rectal cancers before quantitating tumour permeability (ln Ktrans) by DCE-MRI. Sixteen patients receiving preoperative chemoradiotherapy had serial vascular endothelial growth factor (VEGF) and DCE-MRI measurements. Response to treatment was assessed using World Health Organization criteria.

RESULTS

Serum VEGF and ln Ktrans correlated before treatment (r = 0.48, P = 0.01). Responsive tumours (n = 8) had higher pretreatment permeability values than non-responsive tumours (n = 8) (mean ln Ktrans - 0.46 and - 0.72 respectively; P = 0.03). Compared with pretreatment values, responsive tumours showed a marked reduction in permeability at the end of treatment (mean ln Ktrans - 0.46 and - 0.86 respectively; P = 0.04). Pretreatment serum VEGF levels were not statistically different between the two groups.

CONCLUSION

Rectal tumours with higher permeability at presentation appear to respond better to chemoradiotherapy than those of lower permeability. This may allow preselection of appropriate tumours for these regimens, with patients with low-permeability tumours being considered for alternative therapies.

The prevalence of avascular necrosis in patients treated with chemotherapy for testicular tumours

To study the prevalence of avascular necrosis in patients receiving chemotherapy for testicular cancer we invited 103 consecutive patients treated by chemotherapy to attend for MRI scan of the hips. Four of 47 (9% (CI 2-20%)) patients scanned and 4/103 (3.8% (CI 1-10%)) of patients invited to participate in the study had evidence of avascular necrosis. As not all patients in the study had completed the at risk period this equates to a 3-year actuarial risk of 6.3% (95% confidence limits (CI) 2.4-16.1). These data suggest that avascular necrosis is an uncommon but significant complication of chemotherapy including steroids as anti-emetics.

BOLD MRI of human tumor oxygenation during carbogen breathing

An MRI method is described for demonstrating improved oxygenation of human tumors and normal tissues during carbogen inhalation (95% O2, 5% CO2). T2*-weighted gradient-echo imaging was performed before, during, and after carbogen breathing in 47 tumor patients and 13 male volunteers. Analysis of artifacts and signal intensity was performed. Thirty-six successful tumor examinations were obtained. Twenty showed significant whole-tumor signal increases (mean 21.0%, range 6.5-82.4%), and one decreased (-26.5 +/- 8.0%). Patterns of signal change were heterogeneous in responding tumors. Five of 13 normal prostate glands (four volunteers and nine patients with nonprostatic tumors) showed significant enhancement (mean 11.4%, range 8.4-14.0%). An increase in brain signal was seen in 11 of 13 assessable patients (mean 8.0 +/- 3.7%, range 5.0-11.7%). T2*-weighted tumor MRI during carbogen breathing is possible in humans. High failure rates occurred due to respiratory distress. Significant enhancement was seen in 56%, suggesting improved tissue oxygenation and blood flow, which could identify these patients as more likely to benefit from carbogen radiosensitization.

Dynamic contrast-enhanced MRI studies in oncology with an emphasis on quantification, validation and human studies

Magnetic resonance imaging (MRI), after the administration of an extracellular, gadolinium-based contrast medium, can be used to detect and characterize human tumours. The success of dynamic contrast-enhanced MRI (DCE-MRI) is dependent on its ability to demonstrate intrinsic differences between a variety of tissues that affect contrast medium behaviour. Evidence is mounting that DCE-MRI measurements correlate with immunohistochemical surrogates of tumour angiogenesis. DCE-MRI can monitor the effectiveness of a variety of treatments including chemotherapy, hormonal manipulation, radiotherapy and novel therapeutic approaches including antiangiogenic drugs. Kinetic parameters in the treatment setting have been correlated with histopathological outcome and patient survival. This article reviews quantification analysis of these studies together with current and future clinical applications.